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H
19 tháng 10 2017
Bài 1:
a) \(0,\left(3\right)+3\dfrac{1}{3}+0,4\left(2\right)\)
\(=\dfrac{1}{3}+\dfrac{10}{3}+\dfrac{19}{45}\)
\(=\dfrac{184}{45}\)
b) \(\dfrac{4}{9}+1,2\left(31\right)-0,\left(13\right)\)
\(=\dfrac{4}{9}+\dfrac{1219}{990}-\dfrac{13}{99}\)
\(=\dfrac{1789}{990}\)
Bài 2:
a) \(0,\left(37\right)x=1\)
\(\Leftrightarrow\dfrac{37}{99}.x=1\)
\(\Leftrightarrow x=1:\dfrac{37}{99}\)
\(\Leftrightarrow x=\dfrac{99}{37}\)
b) \(0,\left(26\right)x=1,2\left(31\right)\)
\(\Leftrightarrow\dfrac{26}{99}x=\dfrac{1219}{990}\)
\(\Leftrightarrow x=\dfrac{1219}{990}:\dfrac{26}{99}\)
\(\Leftrightarrow x=\dfrac{1219}{260}\)
Chúc bạn học tốt!
26 tháng 7 2021
\(\dfrac{7}{2}\) : \(\dfrac{2}{5}\) = x : \(\dfrac{8}{7}\)
x : \(\dfrac{8}{7}\) = \(\dfrac{7}{2}\) : \(\dfrac{2}{5}\)
x : \(\dfrac{8}{7}\) = \(\dfrac{35}{4}\)
x = \(\dfrac{35}{4}\) . \(\dfrac{8}{7}\)
x = 10
25 tháng 8 2021
a: Ta có: \(0,\left(3\right)+\dfrac{10}{3}+0,4\left(2\right)\)
\(=\dfrac{1}{3}+\dfrac{10}{3}+\dfrac{4}{9}\)
\(=\dfrac{33}{9}+\dfrac{4}{9}=\dfrac{37}{9}\)
b: Ta có: \(\dfrac{4}{9}+1.2\left(31\right)-0,\left(13\right)\)
\(=\dfrac{4}{9}+\dfrac{1219}{990}-\dfrac{13}{99}\)
\(=\dfrac{440}{990}+\dfrac{1219}{990}-\dfrac{130}{990}\)
\(=\dfrac{139}{90}\)
25 tháng 8 2021
c: Ta có: \(2,\left(4\right)\cdot\dfrac{3}{11}\)
\(=\dfrac{22}{9}\cdot\dfrac{3}{11}\)
\(=\dfrac{2}{3}\)
d: Ta có: \(-0,\left(3\right)+\dfrac{1}{3}\)
\(=-\dfrac{1}{3}+\dfrac{1}{3}\)
=0
22 tháng 2 2017
1.Thực hiện phép tính :
a) -4,3y - \(\frac{1}{2}y-\frac{3}{4}=-0,4\)
=> (-4,3- \(\frac{1}{2}\))y = -0,4 + \(\frac{3}{4}\)
=> \(\frac{-24}{5}\)y = \(\frac{7}{20}\)
=> y = \(\frac{7}{20}:\frac{-24}{5}\)
=> y = \(\frac{-7}{96}\)
b) 4\(\left(y-\frac{1}{3}\right)^3=0\)
=> y3 - \(\frac{1}{3}^3\) = 0
=> y3 - \(\frac{1}{27}=0\)
=> y3 = \(\frac{1}{27}\)
=> y = \(\frac{1}{3}\)
c) 13 -2 . | 1 - 2y | = 1
=> 2.| 1 - 2y | = 13 - 1
=> 2.| 1 - 2y | = 12
=> | 1 - 2y | = 6
=> \(\left[\begin{matrix}1-2y=6\\1-2y=-6\end{matrix}\right.\)
=> \(\left[\begin{matrix}2y=-5\\2y=7\end{matrix}\right.\)
=> \(\left[\begin{matrix}y=\frac{-5}{2}\\y=\frac{7}{2}\end{matrix}\right.\)
VM
22 tháng 2 2017
Bài 1:
a)\(\frac{-4}{3}.y.\frac{-1}{2}.y.\frac{-3}{4}=-0.4\)
\(\Leftrightarrow\frac{-4}{3}.\frac{-3}{4}.\frac{-1}{2}.y^2=\frac{-2}{5}\)
\(\Leftrightarrow\frac{-1}{2}y^2=\frac{-2}{5}\)
\(\Leftrightarrow y^2=\frac{4}{5}\)
\(\Leftrightarrow\left[\begin{matrix}y=\sqrt{\frac{4}{5}}\\y=-\sqrt{\frac{4}{5}}\end{matrix}\right.\)
b) \(4.\left(y-\frac{1}{3}\right)^3=0\)
\(\Leftrightarrow\left(y-\frac{1}{3}\right)^3=0\)
\(\Leftrightarrow y-\frac{1}{3}=0\)
\(\Leftrightarrow y=\frac{1}{3}\)
c) 13-2.|1-2y|=1
<=>2.|2y-1|=12
<=>|2y-1|=6
<=> \(\left[\begin{matrix}2y-1=6\\2y-1=-6\end{matrix}\right.\)
<=>\(\left[\begin{matrix}y=3,5\\y=-2,5\end{matrix}\right.\)
1 tháng 10 2021
a: \(0.4\cdot\sqrt{0.25-\sqrt{\dfrac{1}{4}}}=0.4\cdot\sqrt{0.25-0.5}\)(đề này sai rồi bạn)
b: \(\dfrac{3}{2}+2\left(x-1\right)=-5\dfrac{1}{2}\)
\(\Leftrightarrow2\left(x-1\right)=\dfrac{-11}{2}-\dfrac{3}{2}=-7\)
\(\Leftrightarrow x-1=\dfrac{-7}{2}\)
hay \(x=-\dfrac{5}{2}\)
LK
2
2 tháng 9 2019
c) 3,6-|x-0,4|=0
|x-0,4|=3,6-0
|x-0,4|=3,6
* x-0,4 =3,6 * x-0,4=-3,6
x=3,6+0,4 x= -3,6+0,4
x=4 x=-3,2
vậy x=4 hoặc x=-3,2
2 tháng 9 2019
a) 2/3 : x + 5/7 = 3/10
=> 2/3 : x = 3/10 - 5/7
=> 2/3 : x = -29/70
=> x = 2/3 : -29/70
=> x = -140/87
b) 3/4 . x - 1/2 = 3/7
3/4 . x = 3/7 + 1/2
3/4 . x = 13/14
x = 13/14 : 3/4
x = 26/21
c) 3,6 - | x - 0,4 | = 0
Có 2 TH :
-) x = 0,4
-) x - 0 ,4 = -3,6
=> x = -3,2
Chúc bn học tốt 😊😊
NT
1
27 tháng 5 2020
a) \(\frac{4}{5}\)✖\(\left(\frac{7}{2}+\frac{1}{4}\right)^2\)
= \(\frac{4}{5}\)✖ \((\frac{15}{4})^2\)
= \(\frac{4}{5}\)✖ \(\frac{225}{16}\)
= \(\frac{1}{1}\times\frac{45}{4}\)
= \(\frac{45}{4}\)
G
3 tháng 3 2018
Câu 2 đây:
\(|x^2+|x-1||=x^2+2\)
\(\Rightarrow\orbr{\begin{cases}x^2+\left|x-1\right|=x^2+2\\x^2+\left|x-1\right|=-x^2-2\left(l\right)\end{cases}}\)
\(\Rightarrow\left|x-1\right|=2\Leftrightarrow\orbr{\begin{cases}x=3\\x=-1\end{cases}}\)
KT
3 tháng 3 2018
a) \(M=\left(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+0,5}{1\frac{1}{6}-0,875+0,7}\right):\frac{2012}{2013}\)
\(=\left(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{2}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\right):\frac{2012}{2013}\)
\(=\left(\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}-\frac{2\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\right):\frac{2012}{2013}\)
\(=\left(\frac{2}{7}-\frac{2}{7}\right):\frac{2012}{2013}\)
\(=0\)
HT
1
22 tháng 5 2022
c: \(\dfrac{x-2}{x-1}=\dfrac{x+4}{x+7}\)
=>(x-2)(x+7)=(x+4)(x-1)
\(\Leftrightarrow x^2+5x-35=x^2+3x-4\)
=>5x-35=3x-4
=>2x=31
hay x=31/2
h: \(\dfrac{3x+2}{5x+7}=\dfrac{3x-1}{5x-3}\)
\(\Leftrightarrow\left(3x+2\right)\left(5x-3\right)=\left(3x-1\right)\left(5x+7\right)\)
\(\Leftrightarrow15x^2-9x+10x-6=15x^2+21x-5x-7\)
=>x-6=16x-7
=>-15x=-1
hay x=1/15
gn ugneg hg8ug
\(\frac{31}{2}\div0,4=x\div1\frac{1}{7}\)
\(\frac{31}{2}\div\frac{2}{5}=x\div\frac{8}{7}\)
\(\frac{155}{4}=x\div\frac{8}{7}\)
\(x=\frac{155}{4}\times\frac{8}{7}\)
\(x=\frac{310}{7}\)